Loading, quenching, and surging

To: "'Tesla List'" <tesla-at-pupman-dot-com>
Subject: Loading, quenching, and surging
From: Tesla List <tesla-at-stic-dot-net>
Date: Sat, 7 Mar 1998 17:24:34 -0600
Approved: tesla-at-stic-dot-net

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From:  Rick L. Kirby [SMTP:rkirby-at-earthlink-dot-net]
Sent:  Saturday, March 07, 1998 10:50 AM
To:  Tesla List
Subject:  Re: Loading, quenching, and surging

Tesla List wrote:
> 
> ----------
> From:  FutureT [SMTP:FutureT-at-aol-dot-com]
> Sent:  Friday, March 06, 1998 8:04 AM
> To:  tesla-at-pupman-dot-com
> Subject:  Loading, quenching, and surging
> 
> All,
> 
> Many have discussed the importance of spark loading for good quenching,
> and I think my latest coil demonstrates this is an intriquing way.  I'm using
> a two gap sync rotary at 60 BPS, and obtaining 45" sparks at 600 watts.
> 
> Often the sparks are shorter than 45", and at these times, the gap arcs
> are very bright indicating poor loading and subsequent poor quenching.
> Then as the coil runs, a random spark often reaches out a little farther,
> which causes the loading to improve, which improves the quenching,
> making the gap arcs dimmer.  As the quenching improves, the extra
> energy going into the arc lengthens it even more, which in turn improves
> the loading and the quench.  So a positive feedback condition is occuring
> which eventually propels the spark out to the full 45", and the gap arcs
> are very dim by this time, indicating excellent quenching.  Finally, the
> spark hits the measuring wire, the loading is adversely affected, and
> the gaps brighten, and the process is free to begin again.  In addition,
> the longer sparks may be improving the tuning of the coil, adding still
> another factor to the positive feedback loop.  The loudness of the coil
> also increases during the long spark, good quenching times, reflecting
> the extra energy going into the streamers.
> 
> This process may be occuring in many coils, but may not be so
> pronounced.  It is possible that the 60 BPS break rate slows the
> process so it is more easily seen.  It is also probably important to
> use a somewhat marginally quenching gap to make the process more
> noticeable.  I've noticed that when I use better quenching series rotaries,
> the gap tends to run at a more constant brightness, and the sparks tend
> to be more equal in length with less surging.  I actually find the surging-
> type operation gives a more interesting and impressive display, and some
> visitors who saw the coil in operation strongly agreed.  I've noticed that
> many large coils tend to surge in this way.  Maybe the characteristic
> is enhanced in large coils, or maybe the quenching was marginal in
> those coils.  I think this surging effect is at least a partial explanation
> for those *rare long sparks* that people refer to.
> 
> I've seen this surging in some of my previous coils, but to a lesser
> degree. I'd be interested to hear if anyone has seen this effect in
> their coils.  Comments welcomed as always.
> 
> John Freau

John

	My new 6" coil w/26"x 6" toroid running 4 - 15kv/30ma nst's and
 a copper pipe variable speed vacuum gap, surges as it runs, it averages
 about 50" and surges out to 60"-62". I agree the surging is more
interesting
 to see and hear. Sometimes I see the one bolt that surges out in about
3 pulses
 that is very straight with a large trunk and small fingers along the
sides. 

	Thanks for your excellent vidio tape #20 I enjoyied it. 

:^)

Rick Kirby